


Sibling Rivalry

by thelogicoftaste



Category: Teen Wolf (TV)
Genre: Dad!Derek, Kid Fic, Kid!Boyd, Kid!Isaac, Lydia Stiles and Isaac are Siblings, M/M
Language: English
Status: Completed
Published: 2015-01-15
Updated: 2015-01-15
Packaged: 2018-03-07 17:49:41
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,689
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3177904
Author URL: https://archiveofourown.org/users/thelogicoftaste/pseuds/thelogicoftaste
Summary: <blockquote class="userstuff">
              <p>“Stiles,” he says seriously. “Don’t be a dick.”</p>
            </blockquote>





	Sibling Rivalry

**Author's Note:**

  * For [En_Kelleher](https://archiveofourown.org/users/En_Kelleher/gifts).



> This is for Nicole, who is recovering from a surgery. I sneakily sent her an anon message asking what her favourite Sterek fic tropes were so I could write her this. 
> 
> Nicole, I added in as many tropes as I could, love you tons, I hope you get better. ♡
> 
> Also to my sister, who is an asshole.

-

Stiles is always, invariably, the last one to get up.

It’s not like he doesn’t try to be a better person – one who wakes up early, and drinks smoothies and shit – and his YouTube history would attest to that. But Stiles … he likes his bed. He likes to sleep, he likes to lie within his sheets and scroll endlessly on the internet, perhaps even get in a cheeky little jerk off session if he has the time.

What he emphatically does _not_ like is his dorktastic seven-year-old little brother cracking open his door in the morning.

Isaac tries to be stealthy, but the fact of the matter is that the kid has all the subtlety of an overgrown elephant, and apparently, the feet of one too. Each step that Isaac takes closer is like the death toll of reality that Stiles wants to avoid at all costs. He’s groaning before Isaac even reaches his bedside.

“I know you’re awake,” Isaac says, and Stiles can only imagine the bratty look on his face.

Still, he feigns ignorance.

“Stiles,” Isaac whines, shaking him by the shoulder. “It’s practice today, and you promised you’d coach again.”

Isaac’s original coach, and coincidentally Stiles’ Econ teacher from high school, is a strange old man; one whom had involved himself in a precarious situation comprising of cupcakes and Stiles’ old college roommate, Greenberg, that resulted in two broken legs and an accident report that has Scott giggling to this day.

Stiles doesn’t want to know.

Okay.

He wants to know a little bit.

_But-_

That’s not the point.

The point is that when he’d promised Isaac to take over the management of the Beacon Hills Little League squadron of squealing seven year olds he hadn’t foreseen: a) getting so drunk the previous night, and indulging in a ‘fun’ night out with his friends which more or less ended up with Stiles commandeering a table in order to simultaneously cry whilst dancing the Dougie; b) making out with not one, but _two_ of the bouncers at _Jungle_ , (the coinciding of these events is yet to be determined) and c) seeing his very recent douchebag of an ex the day before, which thus prompted both a and b.

“Stiles,” Isaac says again, slapping his hand over the top of the duvet. “Come _on_ , you promised.”

“I’m going,” Stiles says, though he has yet to open his eyes. “Give me ten minutes.”

Isaac paws the duvet away, uncovering Stiles’ face.

“Stiles,” he says seriously. “Don’t be a dick.”

Stiles cracks his eye open, “Who taught you that?”

“I’m seven,” Isaac tells him, rolling his eyes. “I’m not a baby.”

Stiles, however, apparently still is, because he mimics him childishly, a whole string of high-pitched gibberish that sounds nothing like Isaac whatsoever. Stiles smacks his lips tiredly and shuffles in deeper into the warmth of his duvet rather than dealing with his younger brother’s foul mouth.

But Isaac doesn’t desist. Instead, he leans into Stiles bedspread, continues conversationally, “Lydia calls you an asshole all the time.”

“Lydia,” Stiles retorts mulishly, “is both older and more terrifying than you and I will ever be. In fact,” Stiles says, never missing an opportunity to be a dick, “you should go tell dad what she’s been teaching you.”

Isaac considers this.

He considers it seriously.

Finally, he side-eyes Stiles, “Will you buy me the new World of Warcraft game?”

“What?” Stiles exclaims, eyes flying open. “ _No_.”

“Well then,” Isaac replies easily, standing up from his slouch. “I’m going to tell dad that you told me to say asshole and call people dicks and _bastard_ and _fucker_.”

With that, Isaac darts out of Stiles’ room.

It takes only a second, but as soon the words sink into Stiles’ understanding he’s whipping off his duvet and surging upright like a man possessed.

 _“Isaac!”_ he bellows, thundering after his little brother. “C’mere, _you manipulative little shit!_ ”

-

The day doesn’t get much better than that. The playing field is wet and dreary, the bright sunshine above is positively abhorring, and Stiles just wants to go to sleep.

He and Isaac are holding down the fort as they wait for the team to trickle in. The Sheriff had dropped them off twenty minutes earlier, and Lydia had disappeared some ten minutes before with promises of coffee and bagels.

So now Stiles sprawls in the dugout canopy, legs raised over the seat of another chair, arms draped over his stomach and his sunglasses firmly situated on his face.

Isaac stands beside him, dressed in a puffy parka that engulfs him, a perky purple woollen hat and a scarf that the Sheriff had looped worriedly around his neck.

Stiles peers at him from behind his sunglasses, “You look about as punchable as a piñata.”

Isaac flips him the bird.

Stiles pushes him over.

-

In all honesty, the kids do most of the work in terms of getting warmed up. Stiles guides the kids through jumping jacks and long stretches, sure, but he follows his own instructions a little half-heartedly, more interested is he in sipping his latte and checking his social network notifications.

There’s another team on the other side of the field, though they’re playing basketball, rather than baseball.

Stiles scoffs at the way the children line up neatly, jogging serenely after their coach – a mountain of a man with three-day-old stubble, thick thighs and biceps that go on for days.

Stiles scoffs again, loudly slurping his coffee in protest.

That’s not how juvenile sport should be, he thinks haughtily, all battle cries and overzealous exercises. They’re _children_ , not athletes. He far prefers his own team.

I mean, would Stiles feel a sense of accomplishment, a sense of _proud honour_ , if he didn’t spend his time trying to get little Kira to stop smacking the other kids in the face with her bat and distinct lack of hand-eye coordination, or get Greenberg 2.0 to face the right way during his turn to pitch the ball, or attempt to calm Liam down when he picks a fight with a tree?

No.

No, he wouldn’t.

Stiles is arranging the sports equipment on the bench, as Lydia corrals the children onto the playing field, when he turns around and smacks into a brick wall.

“Jesus _Christ_ ,” Stiles screeches as he rebounds, stumbling back a step and a half. He glares at the culprit, though Stiles feels like his sunglasses hinder the intensity of his scowl somewhat so he whips off his sunglasses and narrows his eyes at the man.

Of course, it’s the man mountain from the other field.

“Do you have a problem?” Stiles demands, before wincing. He presses his hand against the throbbing headache that’s just returned with a vengeance. “Or do you just ordinarily stand in people’s way and destroy the little good they had in their day?”

Man-Mountain looks confused; his mouth opens a little, but absolutely no sound comes out. Instead, his eyebrows twitch slightly as he shifts on his feet. Stiles has been told that he generally inspires perplexity in people, but he has no time for that today.

 _“What_?” he snaps.

Man-Mountain seems to snap out of whatever fugue state he’d fallen into and he frowns, folding his, frankly unnecessary, biceps over his chest. “Are you always this welcoming?”

“Always,” Stiles retorts. “What’s your business?”

Man-Mountain rolls his eyes, but says, “I can see that you have no coach for the team.”

Stiles _squints_ at him.

“Your point being?”

“I know a little about baseball,” Man-Mountain says. “Enough to take over until the Coach comes back.”

Stiles pulls himself up to his full height.

“Thanks,” he drawls, slipping his sunglasses back on. “But I can teach them well enough.”

“You’re wearing skinny jeans,” Man-Mountain says, like that makes any difference.

These babies have seen Stiles through many nights shaking his God-given ass on the dance floor; it’s frankly _insulting_ to insinuate he can’t pitch a few games with them.

“Yeah, well,” Stiles replies. “You’re a little too-,” he pauses, raking his gaze over Man-Mountain’s body; and it’s a formidable body, _damn right_ it is, but Stiles has a face to save.

Man-Mountain rolls his eyes, “Too buff?” he asks sarcastically.

Stiles’ eyebrows lift, trying to portray an air of silent judging even though his brain is pushing thoughts of himself draped all over Man-Mountain’s body to the fore.

“I was going to say brutish,” Stiles lies, and he likes the stunned look on Man-Mountain’s face. He fixes his sunglasses, for nothing other than that it makes him look cool, “But sure, buddy, whatever strokes your ego.”

With that he turns and walks away.

-

Man-Mountain, or Coach Derek, as he’d introduced himself, is surprisingly good with the kids.

The dichotomy between the two groups is palpable, however, and especially when Derek’s kids form a harmonic chorus of _‘Yes, Coach Derek’_ and _‘Thank You, Coach Derek_ ’, whereas Stiles’ group consists of various kids wandering in different directions, Greenberg 2.0 doggedly continuing his jumping jacks and Kira calmly explaining that ‘ _friends aren’t snacks, Malia’_ as Malia attack hugs her from behind and clamps her teeth on Kira’s jersey.

Derek sends him many, _many_ , dirty looks.

Stiles is standing by the side with Lydia, watching the proceedings carefully.

“Sure, he's hot,” Stiles concedes. They’ve been having this conversation for ten minutes now. “But he’s an asshole.”

“You’re an asshole,” Lydia says easily.

“Thanks, sis.”

“And you like assholes,” she continues. “Lord knows you’ve dated enough of them. In fact, you’re an asshole who likes assholes who like assholes.”

Stiles side-eyes her.

“Get it?” Lydia says, nudging him with a wry grin. “Assholes who like assholes as primary sexual zones.”

“I get it,” Stiles cuts in, in an effort to make her _stop_. He takes deep breath, “ _Anyway;_ I don't really think he's an asshole.”

“I know,” Lydia tells him. “He’s good with the kids, he has a fantastic ass, and I’m pretty sure there are some well-defined abs lurking beneath his shirt.”

“Oh, there _are_ ,” Stiles agrees, he’d spent more than a little while ogling the planes of Derek’s stomach when his shirt had ridden up during one of the stretches. “But his smile is nice too.”

“Yeah,” Lydia sighs. She turns to Stiles, “You though, you’re definitely an asshole.”

-

Isaac wanders up to Stiles sometime time in the second inning, hand in hand with a little black boy.

He’s a little taller than Isaac, with his hair cropped close to his dark forehead and a very serious expression.

“This is Boyd,” Isaac says dutifully. “He’s my best friend.”

Stiles thought Catherine from school was Isaac’s best friend, but who is he to comment.

“Hi, Boyd,” Stiles says, perching his sunglasses on his head to smile down at the kid. “How’re you doing?”

“I’m okay,” Boyd says. “My dad says I should thank you for letting us join your team for today.”

“Your dad?” Stiles asks, brows furrowing. He looks to the stand, but it’s empty as usual and there are no other adults here other than Lydia and-

“Coach Derek,” Isaac says triumphantly, gazing adoringly at where Derek is guiding the kids through another set of drills. “That’s his dad, isn’t it cool?”

Stiles looks at Boyd.

He looks at Derek.

He looks at Boyd, then at Derek, then at Boyd again.

“Oh,” he mutters under his breath when it hits him. “The kid’s adopted, _obviously_.”

“What?” Boyd falters.

Stiles snaps his eyes to the kid, watching as Boyd’s face shutters down and Stiles thinks _shit._

 _Oh fucking shit_.

“I-,” Stiles says. “Boyd. I-”

Stiles has no idea how to fix this. His heart beats double fast and he panics. He’s fucked up this child’s entire life and Derek is going to rip out his intestines. Rip them clean out and Stiles will have to move out of Beacon Hills because everyone will know that he ousted a kid’s adoption. No one will ever look at him the same way again. He will never get _laid_ ever again. He’ll have to turn to involuntary celibacy because he, Stiles R. Stilinski, is the destroyer of the blissful ignorance of adopted children.

Boyd’s eyes are big and round, gazing up at Stiles with fragile softness.

“I’m adopted?” he asks, bottom lip trembling. He turns to where Derek is, before looking at Stiles, “But-, what?”

Stiles starts hyperventilating, and by this point his eyes are just as big and round as Boyd’s own. He casts his gaze around frantically, but Lydia is busily texting in the dugout and Derek’s unaware that he is soon going to have to kill a man for hurting his child’s feelings.

“Boyd, no,” Stiles says frantically, shooting a panicked look at Isaac. “I’m sure it’s just a misunderstanding. Oh god, please don’t let Derek kill me.”

But Boyd is just shaking his head, mouth pressed tight as a single tear falls over his cheek.

“Kid,” Stiles tries next, crouching down to Boyd’s eye level. “Kid, listen to me. Yeah? I was just playing around," he laughs uneasily. "Look at you,” Stiles exclaims frantically. “You look just like your dad!”

Boyd stops, glancing up at Stiles, and then his shoulders start shaking.

Stiles is - somewhat taken aback.

Boyd’s shoulders are shaking, not with tears, but with  _laughter_.

And Isaac’s right there with him.

Boyd slaps a hand on Stiles’ shoulder, laughing so much that his head dips forward.

“You hear that, Isaac? I look like my dad,” Boyd repeats, pinching the bridge of his nose with his pudgy fingers as he shakes his head. Isaac’s too busy holding his belly as he guffaws his way into next week.

They walk away like this, arms thrown over each other, as they laugh, stumbling punch drunk on laughter, back to the others.

“Good one, Boyd,” Isaac snickers. “Did you see his _face?_ ”

Stiles is still kneeling on the grass, staring after them. Did he really just get played by a seven year old?

“What?” Stiles says.

-

It’s barely past noon, the following week, and Stiles is hiding out by the printers eating a bagel from the coffee shop down the block.

Technically, Stiles is a budding journalistic reviewer at the _Beacon Hills Gazette_. Truthfully, he eats more than he should and absolutely destroys everyone in his Facebook group playing Candy Crush.

Allison sneaks up to him, poking him in the ribs. She has an apple, and a bright dimpled smile.

“So a little birdy told me that you’re liking a new guy,” she says, leaning against the other printer.

“The little birdy,” Stiles tells her, whipping out his phone to send Lydia a strongly worded text message, “is full of lies and betrayal.”

“But she’s not wrong about this,” Allison says, biting into her apple. “Is she?”

“You know _nothing_ , Argent.”

“What do you like most about Derek, then?” she asks. “His eyes? His arms? Oh, but he does have very shapely legs too.”

“Very shapely legs?” Stiles asks. “What are you, eighty? And how do you know what kind of legs he has?”

“Lydia has him on Facebook.”

Stiles freezes, Derek has a Facebook account? Is today his lucky day? Should Stiles get down on his knees and bow down to the universe?

He very subtly unlocks his iPhone screen. It’s been a long time since he’s been on Facebook anyway; checking his twin's Facebook, for _reasons,_ is nothing out of the ordinary.

Allison snorts a laugh, “I already have his profile loaded.”

Stiles scrambles to her side, and they spend the next twenty minutes stalking Derek’s profile.

There are a lot of pictures of Boyd, of him on his Dad’s back, in his basketball uniform, in front of a birthday cake. This comes alongside various pictures of a huge family congregated together and pictures of Derek smiling; it makes Stiles’ all aflutter.

But then-

 _Fuck,_ is that Derek on a _motorcycle?_

-

Stiles learns two days later that Boyd, darling little Boyd, aside from being a sportsman and expert prankster, is a budding actor.

He’s in the living room with Isaac, practicing his lines for his school play, while Stiles passive-aggressively cuts their sandwiches.

Boyd is apparently playing a werewolf – scratch that, a dying werewolf, if his screams are anything to go by.

Of course, the girl playing the lead knight is the love of Boyd’s young life, so “this has to be perfect, Isaac, just perfect.”

“It will be,” Isaac assures him. “You can win Erica’s heart when you slay the evil king to save the children. Girls can’t resist a noble quest, you know.”

Boyd nods knowingly.

When Derek comes to pick Boyd up from the play-date later in the evening, wearing a soft-looking pull over and a hesitant smile, Stiles is at his wits end.

He didn’t graduate college to run after two rambunctious children. He doesn’t deserve to be smeared with peanut butter jelly, and by all that’s good in the world he doesn’t deserve to sit through three hours of _Clarence_.

But still, he invites Derek in, and it takes quite a bit of discipline not to ogle Derek’s fine butt for longer than ten seconds. They settle in the kitchen, and Stiles asks, “You drink coffee?"

Because the kids are passed out on the couch and Stiles unashamedly wants to keep Derek around for a little longer.

Derek nods, commenting, “You seem a little more forthcoming this time around.”

Stiles is busily pouring coffee beans into the machine, he asks, distractedly, “What do you mean?”

“You’re-,” Derek seems to be finding his words; he shrugs a little when Stiles turns to him. “You’re being friendly.”

Stiles snorts, “When have I not been friendly?” Then, he remembers his and Derek’s first meeting. “Ah.”

“Yeah,” Derek says.

“I was having a bad day,” Stiles explains weakly, pressing the button of the coffee machine. “I get like that, sometimes.”

“Hangovers?” Derek asks with a knowing look.

“Oh _yeah_ ,” Stiles agrees.

Relieved that the awkward tension has been lifted, Stiles sprawls on the seat opposite Derek.

“So,” he says, tapping his fingers on the table. “Boyd.”

Derek peers curiously at him, “He’s … he’s my child, yes?”

“He’s a very talented kid,” Stiles tells Derek with a smile. “Very talented in acting. In playing _pranks_ in particular.”

Derek groans, head falling into his hands.

“Was it the adoption thing again?” he asks, words muffled into his palms. “I’ve told him to stop doing that.”

-

The bar that Lydia tells Stiles to go to on Friday is one he’s never been to before, but it seems nice enough when he and Scott finally roll around late in the evening.

Lydia is already there, of course, with Allison on one side and Jackson on the other. What’s surprising, however, is that Derek is there too, alongside his sister, Cora, whom Stiles definitely did not stalk on Facebook to determine whether or not she was Derek’s significant other.

“What’s he doing here?” Stiles asks Lydia as Scott slides into the booth.

Derek tenses in his seat and Lydia narrows her eyes, “Don’t be rude to Derek,” she says. “I invited him as a thank you for coaching your disastrous little league team.”

“Not him,” Stiles says, rolling his eyes, he points to Jackson, “ _Him_. I _hate_ him.”

Jackson laughs, an obnoxious roll of a thing, “Very funny,” he drawls, pointedly wrapping an arm around Lydia.

Stiles gets the first round, likes the feeling of alcohol flowing hot in his veins – but he likes it even better when everybody shuffles around and he gets to sit pressed up close to Derek.

Conversation with Derek is easy, and it’s nice seeing him loosen up enough to relax into the atmosphere of the bar. He blushes easily, Stiles notes, when he’s got a bit of liquid in him, and that stubble isn’t fooling anyone.

Two rounds in, and Stiles is pleasantly tipsy. He’s leaning on Derek’s shoulder, but Derek is leaning towards him too. They’re practically in their own bubble, talking quietly amongst themselves. Stiles can’t keep the grin off of his face, and he glances at Derek from beneath his lashes.

He wants to kiss him, but not _now_ in front of everybody. Derek seems to want the same thing, because he leads Stiles out later and he presses him to the façade of the building.

Derek is strong and solid, boxing Stiles in on either side.

“I thought you didn’t like me,” Derek says, as Stiles curls his fingers into Derek’s belt hoops, pulls him closer.

“I’m an asshole,” Stiles says, lips barely brushing over Derek’s. “I’m quite frequently a misanthropist. I don’t like exercise, mornings or hangovers, and I especially don’t like exercising in the mornings with a hangover.”

“But you like me,” Derek surmises.

“I like you,” Stiles nods. He presses a chaste kiss to Derek's mouth before turning them, so that he’s pressing Derek to the wall instead.

Derek has his head tilted back against the wall, thick eyelashes fanning over his cheekbones, and ushering lazy breaths through his reddened lips. He licks them now that Stiles’ gaze is focused solely on them and Stiles can’t help but trace his fingertips over his mouth, carefully tracing the contours and the minute definitions of Derek’s lips.

Derek smiles lazily, broad chest heaving, the corners of his mouth tilted ever so slightly up and his lips are slackening with the heavy lift of each rolling breath.

And Stiles wants to kiss him _stupid_ , just press him up against the wall and press his mouth on to his until they’re both numb and warm with the vestiges of adrenaline and endorphins.

Honestly, this is Scott McCall levels of soppy, disgustingly romantic feelings and it’s seriously killing Stiles’ street cred.

Derek’s mouth is slack and gentle, and Stiles is so close he can see the fine lines of Derek’s lips, the delicate moisture at the parting, his teeth peeking out just slightly, and the individual whiskers of Derek’s ever-present beard framing around them. 

He leans in, heart beating hard and fast in anticipation, and corny as it may be, Stiles doesn’t think it could get any better than this. 

-


End file.
